combination: num. of integers > 6000 formed w/ digits 3,5,6,7,8 w/o reps.

the number of integers greater than 6000 that can be formed using the digits 3,5,6,7,8 without repetition.

answer is 192 . how

bestuser said:

the number of integers greater than 6000 that can be formed using the digits 3,5,6,7,8 without repetition.

answer is 192 . how

Click to expand...

The problem statement is incomplete.

Can we have 4 digit numbers and 5 digit numbers? From the answer, I surmise that both 4 digit and 5 digit numbers are allowed!

Let's attack 5 digit numbers first - any 5 digit number would be greater than 6000.

Number ways we can make 5 digit numbers from this set = 5 * 4 * 3 * 2 * 1 (why?)

Now you tell us about the 4 digit numbers. The thousand digit can be selected in 3 ways (6, 7 & 8) .... and continue....